// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_RENDERER_HOST_PEPPER_BROWSER_PPAPI_HOST_IMPL_H_
#define CONTENT_BROWSER_RENDERER_HOST_PEPPER_BROWSER_PPAPI_HOST_IMPL_H_

#include <map>
#include <string>
#include <unordered_map>
#include <utility>

#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/process/process.h"
#include "content/browser/renderer_host/pepper/content_browser_pepper_host_factory.h"
#include "content/browser/renderer_host/pepper/ssl_context_helper.h"
#include "content/common/content_export.h"
#include "content/common/pepper_renderer_instance_data.h"
#include "content/public/browser/browser_ppapi_host.h"
#include "content/public/common/process_type.h"
#include "ipc/message_filter.h"
#include "ppapi/features/features.h"
#include "ppapi/host/ppapi_host.h"

#if !BUILDFLAG(ENABLE_PLUGINS)
#error "Plugins should be enabled"
#endif

namespace content {

class CONTENT_EXPORT BrowserPpapiHostImpl : public BrowserPpapiHost {
public:
    class InstanceObserver {
    public:
        // Called when the plugin instance is throttled or unthrottled because of
        // the Plugin Power Saver feature. Invoked on the IO thread.
        virtual void OnThrottleStateChanged(bool is_throttled) = 0;

        // Called right before the instance is destroyed.
        virtual void OnHostDestroyed() = 0;
    };

    // The creator is responsible for calling set_plugin_process as soon as it is
    // known (we start the process asynchronously so it won't be known when this
    // object is created).
    // |external_plugin| signfies that this is a proxy created for an embedder's
    // plugin, i.e. using BrowserPpapiHost::CreateExternalPluginProcess.
    BrowserPpapiHostImpl(IPC::Sender* sender,
        const ppapi::PpapiPermissions& permissions,
        const std::string& plugin_name,
        const base::FilePath& plugin_path,
        const base::FilePath& profile_data_directory,
        bool in_process,
        bool external_plugin);
    ~BrowserPpapiHostImpl() override;

    // BrowserPpapiHost.
    ppapi::host::PpapiHost* GetPpapiHost() override;
    const base::Process& GetPluginProcess() const override;
    bool IsValidInstance(PP_Instance instance) const override;
    bool GetRenderFrameIDsForInstance(PP_Instance instance,
        int* render_process_id,
        int* render_frame_id) const override;
    const std::string& GetPluginName() override;
    const base::FilePath& GetPluginPath() override;
    const base::FilePath& GetProfileDataDirectory() override;
    GURL GetDocumentURLForInstance(PP_Instance instance) override;
    GURL GetPluginURLForInstance(PP_Instance instance) override;
    void SetOnKeepaliveCallback(
        const BrowserPpapiHost::OnKeepaliveCallback& callback) override;

    // Whether the plugin context is secure. That is, it is served from a secure
    // origin and it is embedded within a hierarchy of secure frames. This value
    // comes from the renderer so should not be trusted. It is used for metrics.
    bool IsPotentiallySecurePluginContext(PP_Instance instance);

    void set_plugin_process(base::Process process)
    {
        plugin_process_ = std::move(process);
    }

    bool external_plugin() const { return external_plugin_; }

    // These two functions are notifications that an instance has been created
    // or destroyed. They allow us to maintain a mapping of PP_Instance to data
    // associated with the instance including view IDs in the browser process.
    void AddInstance(PP_Instance instance,
        const PepperRendererInstanceData& renderer_instance_data);
    void DeleteInstance(PP_Instance instance);

    void AddInstanceObserver(PP_Instance instance, InstanceObserver* observer);
    void RemoveInstanceObserver(PP_Instance instance, InstanceObserver* observer);

    void OnThrottleStateChanged(PP_Instance instance, bool is_throttled);
    bool IsThrottled(PP_Instance instance) const;

    scoped_refptr<IPC::MessageFilter> message_filter()
    {
        return message_filter_;
    }

    const scoped_refptr<SSLContextHelper>& ssl_context_helper() const
    {
        return ssl_context_helper_;
    }

private:
    friend class BrowserPpapiHostTest;

    // Implementing MessageFilter on BrowserPpapiHostImpl makes it ref-counted,
    // preventing us from returning these to embedders without holding a
    // reference. To avoid that, define a message filter object.
    class HostMessageFilter : public IPC::MessageFilter {
    public:
        HostMessageFilter(ppapi::host::PpapiHost* ppapi_host,
            BrowserPpapiHostImpl* browser_ppapi_host_impl);

        // IPC::MessageFilter.
        bool OnMessageReceived(const IPC::Message& msg) override;

        void OnHostDestroyed();

    private:
        ~HostMessageFilter() override;

        void OnKeepalive();
        void OnHostMsgLogInterfaceUsage(int hash) const;

        // Non owning pointers cleared in OnHostDestroyed()
        ppapi::host::PpapiHost* ppapi_host_;
        BrowserPpapiHostImpl* browser_ppapi_host_impl_;
    };

    struct InstanceData {
        InstanceData(const PepperRendererInstanceData& renderer_data);
        ~InstanceData();

        PepperRendererInstanceData renderer_data;
        bool is_throttled;

        base::ObserverList<InstanceObserver> observer_list;
    };

    // Reports plugin activity to the callback set with SetOnKeepaliveCallback.
    void OnKeepalive();

    std::unique_ptr<ppapi::host::PpapiHost> ppapi_host_;
    base::Process plugin_process_;
    std::string plugin_name_;
    base::FilePath plugin_path_;
    base::FilePath profile_data_directory_;

    // If true, this refers to a plugin running in the renderer process.
    bool in_process_;

    // If true, this is an external plugin, i.e. created by the embedder using
    // BrowserPpapiHost::CreateExternalPluginProcess.
    bool external_plugin_;

    scoped_refptr<SSLContextHelper> ssl_context_helper_;

    // Tracks all PP_Instances in this plugin and associated data.
    std::unordered_map<PP_Instance, std::unique_ptr<InstanceData>> instance_map_;

    scoped_refptr<HostMessageFilter> message_filter_;

    BrowserPpapiHost::OnKeepaliveCallback on_keepalive_callback_;

    DISALLOW_COPY_AND_ASSIGN(BrowserPpapiHostImpl);
};

} // namespace content

#endif // CONTENT_BROWSER_RENDERER_HOST_PEPPER_BROWSER_PPAPI_HOST_IMPL_H_
